A software defined network (SDN) is a new network architecture, and is being increasingly studied and applied, and a current SDN is implemented mainly based on the OpenFlow (openflow) protocol. An SDN network based on the OpenFlow protocol is referred to as an OpenFlow network below, and the OpenFlow network includes an openflow controller (OFC) and an openflow switch (OFS). The OFS maintains a flow table (Flow Table) locally, where the flow table includes multiple flow entries. If a packet to be forwarded has a corresponding flow entry in the flow table, the packet is forwarded according to the flow table, and if there is no corresponding flow entry in the flow table, the OFS requests an instruction from the OFC, the OFC delivers a flow entry in the flow table to the OFS after receiving the request of the OFS, and the OFS obtains the delivered flow entry and then adds the flow entry to a flow table, so as to forward the packet according to a new flow table.
In an OpenFlow network, an OFS generally needs to acquire an initial flow table (that is, the OFS sends a request to an OFC, and the OFC delivers a flow entry after receiving the request), so that the OFS can forward a packet. In the prior art, generally, a flow table is acquired in a manner that a control plane is separated from a data plane.
Refer to FIG. 1, which is a schematic diagram of an architecture of an OpenFlow network in the prior art, which includes an OFC, a conventional switch, multiple OFSes (an OFS1 to an OFS6), where the conventional switch, the OFS1 to the OFS6, and the OFC form a control plane, and the OFS1 to the OFS6 and the OFC form a data plane. The OFS first initializes, in working mode of the conventional switch and based on a protocol such as the Link Layer Discovery Protocol (LLDP) or the Spanning Tree Protocol (STP), the control plane, that is, various OpenFlow control messages are forwarded by using a forwarding table generated by using a protocol such as the STP, after the control plane is initialized, the OFC may deliver an initial flow entry to the OFS by using the control plane, and the OFS receives the flow entry and then adds the flow entry to a flow table of the OFS, so as to acquire an initial flow table. Further, a packet is processed according to the flow table, and the packet is forwarded by using the data plane.
In the prior art, a control plane and a data plane are two different physical networks, and one or more conventional switches are further required, which increases hardware costs; in addition, two network management systems further need to be maintained for the two physical networks, which also increases maintenance costs.